1. Field of the Invention
The present invention relates to a multi-channel audio system using a number of speakers such as a home theater system, for example. In particular, the present invention relates to connection between an audio signal output apparatus and speakers used for such system. Further, the present invention also relates to an electronic apparatus fitted with audio signal output terminals suited for application to a multi-channel audio system, a connector apparatus, and connecting cables used therefor.
2. Description of the Related Art
In recent years, such a multi-channel speaker system capable of generating acoustic effects similar to effective acoustic output in viewing movies audible in a movie-theater has been introduced for household purposes. For example, when operating a so-called home theater system, six-channel speakers including a bass-output-only channel and a center channel are activated.
FIG. 10 exemplifies an arrangement of a conventional electronic apparatus and speakers installed in a home theater system. More particularly, in an example shown in FIG. 10, a TV monitor 1 is installed in front of a viewer 4, and yet, a DVD player 2 for reproducing a digital versatile disc (DVD) recorded with contents of a movie is installed in the vicinity of the TV monitor 1. A video signal output terminal is connected to a video signal input terminal of the TV monitor 1 to allow movie picture image to be reproduced on the screen of this TV monitor 1.
The above-referred DVD player 2 is provided with six-channel audio signal output terminals comprising a pair of front channels, another pair of rear channels, a center channel, and a bass-output-only channel, where audio signal output terminals corresponding to respective channels are connected to speakers 3FR, 3FL, 3RR, 3RL, 3C, and 3W linked with these channels. These speakers linked with the above-referred channels are disposed as described below, for example.
The above-referred pair of speakers 3FR (for front-right-channel) and the other pair of speakers 3FL (for front-left-channel) are respectively disposed on both sides of the TV monitor 1 across an even distance centering the TV monitor 1 in front of the viewer 4. The above-referred speaker 3C (for center channel) is disposed above or below the TV monitor 1. The above-referred speaker 3RR (for rear-right-channel) and the speaker 3RL (for rear-left-channel) are respectively disposed at a position higher than the position of viewer's ears. Further, the above-referred bass-output-only speaker 3W is disposed beside the TV monitor 1. The bass-output-only speaker 3W may be disposed at any position.
Although illustration is omitted in FIG. 10, the connection between respective audio signal output terminals of the DVD player 2 and the above-referred speakers 3FR, 3FL, 3RR, 3RL, 3C, and 3Wis implemented by means of connecting cables conventionally called “speaker cables”. The audio signal output terminals comprise two terminals, a positive-side terminal and a negative-side terminal. Likewise, the speaker terminals comprise two terminals, a positive-side terminal and a negative-side terminal.
As shown in FIG. 11(A) and (B), in correspondence with the above-referred positive-side terminal and the negative-side terminal, the connecting cable 5 consists of a pair of cables integrated at sheathed portion each comprising a bundle of fine copper wires sheathed with sheathing member 6 made from polyvinyl chloride (PVC), for example.
Usually, a pair of the PVC-covered portions of each of the connecting cable 5, i.e., speaker cables, are split from each other at both ends as shown in FIG. 11 (A) and (B). The sheathing member 6 is stripped off at tip portions of both ends to expose the copper-wire-bundles. Tip portions 7 of the exposed copper-wire-bundles are connected to a pair of audio signal output terminals or a pair of terminals of each speaker unit. Copper-wire-bundles may previously be bonded at the tip portions 7 via a soldering process.
In order to ensure proper connection between audio signal output terminals and a pair of terminals of each speaker unit with correct arrangement of positive and negative polarities, sheathing member 6 for sheathing a pair of copper-wire-bundles of each of the connecting cable 5, i.e., speaker cables, is provided with different patterns as shown in FIG. 11(A) or different coloring as shown in FIG. 11(B).
Identical speaker cables 5 are used for connecting a plurality of audio signal output terminals of an electronic apparatus to the corresponding input terminals of a plurality of speaker units via a conventional method of winding a pair of tip portions 7 of copper-wire-bundles at both ends of the speaker cables 5 onto audio signal output terminals of an electronic apparatus and also onto input terminals of each speaker unit or via another conventional method of pinching the tip portions 7 into corresponding terminals. In this case, such setting operation requires special attention in order to properly connect the speaker cables 5 according to pattern or color of the sheathing material 6 of the speaker cables 5, without inverting the positive and negative polarities.
FIG. 12 exemplifies such a state in which tip portions 7 of exposed copper-wire bundles of the speaker cables 5 are wound to the corresponding audio output terminals of an electronic apparatus via the above-referred connecting method. When executing this method, audio output terminals of an electronic apparatus and corresponding input terminals of each speaker unit are provided with a specific form for allowing the tip portions 7 of exposed copper-wire bundles of the speaker cables 5 to be wound thereon. To ensure the connection, screw bases 8 are provided for each of the input terminals of the speaker units in order to secure the wound-up tip portions 7 of copper-wire-bundles onto the corresponding output terminals.
FIG. 13 exemplifies such a state in which tip portions 7 of exposed copper-wire bundles of the speaker cables 5 are pinched into the corresponding audio output terminals of an electronic apparatus. When executing such method, audio output terminals of an electronic apparatus and corresponding input terminals of each speaker unit are provided with such a structure which causes the tip portions 7 of exposed copper-wire-bundles of speaker cables 5 inserted in through-holes 9 to be pinched by means of metallic spring members functioning as elastically-displaceable terminals for example.
Conventionally, as shown in FIG. 12 or 13, independent of actually arranged positions of speaker units linked with a number of audio signal output terminals, multi-channel audio signal output terminals of an electronic apparatus comprise the one usable for the left and right channels in the front position, the one usable for the left and right channels in the rear position, and yet, also comprise those output terminals solely usable for the center channel and the one solely usable for bass-output channel which are respectively disposed at optional positions.
Nevertheless, as described above, in the case of such a multi-channel audio system corresponding to a home theater system, identical connecting materials, i.e., identical speaker cables, are used even with a plurality of speaker units to be connected. Because of this, connection between the speaker cables and the linking channels can hardly be discerned.
To deal with this problem, it has been a conventional practice to implement such a process, in which, before installing speaker units, speaker units and an electronic apparatus are disposed to be close to each other, and then, while confirming mutual channel relationship, speaker units are connected to the electronic apparatus, and finally, speaker units are respectively installed at specific positions. Further, there has been another method in which, after setting speaker units at specific positions, speaker cables connected to speaker units or to the electronic apparatus are pulled in the direction of the speaker units or the electronic apparatus before eventually connecting the speaker cables to the output terminals of the speaker units or to the output terminals of the electronic apparatus.
Nevertheless, when implementing either of the above methods, inasmuch as it is quite necessary to check and confirm the connecting relationship between individual speaker cables and the corresponding channels, it constitutes an extremely troublesome routine. Because of this, speaker cables were connected to wrong channels.
Further, in order to discern the positive and negative polarities, sheathing member 6 for sheathing copper-wire-bundles of speaker cables is coated with a variety of colors. However, inasmuch as it is optional for individual users to connect copper wires covered with a sheath 6 coated with a specific color to either of both polarities, there has been such a fear of inverting the positive and negative polarities in the connection between the speaker cables 5 and audio signal output terminals of an electronic apparatus and also such a fear of inverting the positive and negative polarities in the connection between the speaker cables 5 and output terminals of the connected speaker units.
Further, as described above, inasmuch as audio signal output terminals of any of conventional electronic apparatuses have not been devised to properly deal with actually disposed positions of individual speaker units per channel, when a plurality of speaker cables 5 are led out from audio signal output terminals in correspondence with the actually disposed positions of individual speaker units, these plural speaker cables 5 cross each other, making it difficult to properly discern the connecting relationship between individual speaker cables 5 and the corresponding output terminals per channel, thus causing confusion to the setting operator when actually connecting individual speaker cables to the output terminals of corresponding speaker units per channel.
For example, as shown in FIG. 12 and 13, in such a case in which audio signal output terminals provided for the front-left-right channels are disposed to the left of an electronic apparatus whereas audio signal output terminals provided for the rear-left-right channels are disposed to the right thereof, assume that speaker cables each being connected to the audio signal output terminals of this electronic apparatus are led out in correspondence with actually disposed positions of speaker units per channel, then, as shown in FIG. 14, speaker cables 5FL connected to speaker units provided for the front-left channel are led from the electronic apparatus across the audio signal output terminals provided for the rear-left-right channels. On the other hand, speaker cables 5RR connected to speaker units provided for the rear-left-right channels are led from the electronic apparatus across the audio signal output terminals provided for the front-left-right channels, whereby causing these two sets of speaker cables to intersect themselves to make it difficult to have them properly aligned with each other.
Yet, as is apparent from an intersecting portion 7c shown in FIG. 14, when tip portions 7 of copper-wire-bundles of respective speaker cables 5 are brought into contact with each other in short-circuit, then, a resultant failure will be caused to the connected electronic apparatus.
Viewing from the front of an electronic apparatus, speaker cables 5FR connected to audio signal output terminals provided for the front-right channel and the other speaker cables 5RR connected to audio signal output terminals provided for the rear-right channel are respectively led from the right-side of the electronic apparatus. However, inasmuch as these speaker cables are exactly identical to each other, while these speaker cables are led to the corresponding speakers per channel, they are subject to intersection with each other, thus confusing setting operator to properly connect individual speaker cables to the corresponding speaker units. This confusion will also be caused when connecting speaker cables to the corresponding speaker units provided for the front-left channel, the rear-right channel, and the center channel as well.
Further, as described above, inasmuch as audio signal output terminals of any of conventional electronic apparatuses have not been devised to properly deal with actually disposed positions of individual speaker units per channel, as shown in FIGS. 12, 13, and 14, even though names of respective channels are shown on the back-panel surface of the electronic apparatus provided with audio signal output terminals, if the setting operator or user is not well versed in the multi-channel audio system, it is feared that the operator becomes confused when determining proper positions for installing speaker units connected to audio signal output terminals per channel.
Further, in the case of applying the multi-channel audio system to a specific purpose such as a home theater system, even when using a plurality of speaker units of the identical kind for multi-channels, in order that acoustics can properly be reproduced in the best acoustic environment, manufacturer of the multi-channel audio system may deliver the whole system by way of adjusting speaker units per channel specifically for the front-left-right channels, the rear-left-right channels, the center channel, and for the bass-output channel, for example.
Nevertheless, as mentioned above, conventionally, there are many cases in which connecting relationship of individual speaker units against corresponding channels is not designated, or even when being designated, the connecting relationship can hardly be discerned, thus causing the setting operator or user to connect such speaker units different from proper channels designed by the manufacturer. This in turn causes intended acoustics to be output improperly from speaker units disposed at proper positions to result in the failure to precisely reproduce original media-source. If it turns out to be so, inasmuch as original media-source can hardly be reproduced with high-fidelity, it is feared that the purchaser of the multi-channel audio system will fail to fully enjoy original acoustic effect intended by the manufacturer.
In order to assuredly reproduce such a high-fidelity acoustic environment, it is quite necessary to check and confirm individual audio signal output terminals of an electronic apparatus per channel and speaker units of the corresponding channels, and yet, it is also necessary to check and confirm the positive-side terminals and the negative-side terminals. Further, connecting operation must be performed with sufficient care not to cause each speaker cable to be short-circuited with adjoining terminals by way of checking and confirming proper positions for disposing individual speaker units. This in turn incurs extreme annoyance and much time to be spent for implementing the whole connecting routines.